Whitaker, 49, had been serving as chief of staff to Sessions since October 2017, CBS reports.

Whitaker previously served as the U.S. Attorney for the Southern District of Iowa from 2004 to 2009 and ran for the U.S. Senate in the Republican primary in 2014. He came in fourth. He also acted as chair for Sam Clovis’s campaign for Iowa state treasurer in 2014, the Washington Post reports. Clovis went on to serve as Trump’s national campaign chairman, and has been interviewed as a witness by Special Counsel Robert Mueller as part of his probe.

Whitaker has previously expressed skepticism about Special Counsel Robert Mueller’s investigation into Russian interference in the 2016 presidential election, the Washington Post reports.

The Post points to a CNN interview Whitaker gave in July 2017, before he became Sessions’ chief of staff.

“So I could see a scenario where Jeff Sessions is replaced with a recess appointment,” Whitaker said in the interview, “and that attorney general doesn’t fire Bob Mueller, but he just reduces his budget to so low that his investigation grinds to almost a halt.”

Whitaker also wrote a column for CNN in August 2017 opining that investigating Trump’s finances was a “red line” that Mueller’s investigation was coming “dangerously close to crossing.”

“It does not take a lawyer or even a former federal prosecutor like myself to conclude that investigating Donald Trump’s finances or his family’s finances falls completely outside of the realm of his 2016 campaign and allegations that the campaign coordinated with the Russian government or anyone else,” Whitaker wrote. “It is time for Rosenstein, who is the acting attorney general for the purposes of this investigation, to order Mueller to limit the scope of his investigation to the four corners of the order appointing him special counsel.”

On Wednesday afternoon, Sen. Chuck Schumer, D-N.Y., tweeted, “Given his previous comments advocating defunding and imposing limitations on the Mueller investigation, Mr. Whitaker should recuse himself from its oversight for the duration of his time as acting attorney general.”

Whitaker also penned a July 2016 opinion column in USA Today stating that as a former prosecutor, he disagreed with former FBI Director James Comey and would have indicted Hillary Clinton over her use of a private email server during her time as U.S. secretary of state.

Whitaker is cited in the August 2017 CNN column as the director of the Foundation for Accountability & Civic Trust, a 501(c)(3) nonprofit “dedicated to promoting accountability, ethics, and transparency in government and civic arenas by hanging a lantern over public officials who put their own interests over the interests of the public good.” The Washington, D.C., nonprofit’s website lists its current executive director as attorney Kendra Arnold, and no other employees are listed.

Whitaker has also been a managing partner of the Des Moines-based law firm Whitaker Hagenow & Gustoff. Now called Hagenow & Gustoff, Whitaker’s biography is still up on the website and says his “areas of concentration include criminal defense and government investigations, immigration, fraud, corporate and transactional, internal corporate investigations, and commercial litigation.”

According to the law firm biography, Whitaker played in the 1991 Rose Bowl as a tight end on the University of Iowa football team, and was awarded the university’s Big Ten Medal of Honor in 1992. He has worked for the law firms Briggs & Morgan in Minnesota and Finely Alt Smith in Iowa, and served as corporate counsel for the Supervalu grocery company from 1998 to 2001.

In 2014, Whitaker joined the advisory board of a patent company, World Patent Marketing, which billed itself as “offering high-quality and affordable patent services to inventors.”

“As a former U.S. attorney, I would only align myself with a first class organization,” said Whitaker in a press release at the time.

The company ran into legal trouble in March 2017 when the Federal Trade Commission brought fraud charges against it. The FTC said that World Patent Marketing had “bilked” consumers out of millions of dollars.

In a stipulated order from the U.S. District Court for Southern Florida filed in May 2018, World Patent Marketing was ordered to pay more than $25 million and banned from providing any innovation promotion services. Whitaker is not named in the order.

Trump tweeted that a permanent replacement for Sessions “will be nominated at a later date.” The Post reports that Whitaker could serve no more than 210 days as an acting attorney general, because he has not been confirmed by the Senate.

We are pleased to announce that Matthew G. Whitaker, Chief of Staff to Attorney General Jeff Sessions at the Department of Justice, will become our new Acting Attorney General of the United States. He will serve our Country well….